MoTeC Global Forum

Hi,

We have M800 on a Chevy LS-1 engine with MSD crank trigger and original Sync sensor.
We've encountered problems in getting the engine running.
We have tried various settings, but the engine just seems back fire or burn gas in exhaust pipes. Sometimes it gets running with the same banging effects.

We have set the timing such that a traditional timing light shows 10 degrees of advance when craning the engine.
The firing order seems to be correct (18726543), also by measuring with the timing light from all the plug wires.
(Cylinders 1 & 6 show 10 deg., 8 & 5 show 280, etc.)

So has anybody got M800, LS-1 and crank trigger working?
And what is then the correct REF & Sync sensor set-up?

Does M800 require expander kit to work with LS-1?
Now we are using wasted spark & One Tooth Per Firing configuration.

Thanks,
Sakke

The LS1 will work fine in wasted spark configuration but you will need to work out your CRIP correctly or you could be 360 degrees out which would mean that the engine will still run but your fuel timing will be in-correct and any individual fuel trims will be applied to the wrong cylinder.
You will need to do a Ref/sync capture to varify that the ref and sync inputs are working and set up correctly. You should also carry out an output test to ensure that the injectors and coils are corectly wired to the corresponding cylinder.
Once you have done this you need to check that there are no diagnostic errors. I would crank the engine (without the fuel pump running) with the spark pugs removed to check that the ECU syncs up ok. YOu can also check the CRIP with a timing light with the engine cranking over.
It is possible to use the original LS1 crank trigger on the LS1 engine.

Hi Again,

The good news is that the engine is running.

But we have a problem, that it doesn't run over 3500 RPM. The spark signal is cut every time you try to raise RPM over it. RPM limit is set to 7800. We are not running the car, just the engine with neutral gear.

We can see with oscilloscope that incoming REF signal (about 5Vpp) starts clipping such that the positive cycle of the wave form is clipped.
Well, we bought a new MSD crank trigger plate and sensor, but the result is the same.

Do you have any ideas what can cause this, and fix it?


Another question: How can we ensure that the CRIP is correct and not 360 degrees wrong, when using wasted spark configuration?
Well.probably by measuring cyl. #1 fuel signal with SYNC signal, but at which point SYNC goes to high level?

Thanks,
-sakke

sakkeM wrote:...
Another question: How can we ensure that the CRIP is correct and not 360 degrees wrong, when using wasted spark configuration?\
...

Is it possible to know the crank position within 720 degrees without cam position?

Use inlet runner pressure as kawasaki do